Abstract A computer-implemented method of performing an interactive valuation of a saleable commodity, such as a real estate property, said method comprising : receiving one or more descriptors to allow for identification of said saleable commodity; retrieving valuation data corresponding to one or more comparable saleable commodities; presenting to a user said valuation data corresponding to each of said comparable saleable commodities; enabling said user to rank said saleable commodity relative to said comparable saleable commodities based upon said valuation data; and assigning a listing value to said saleable commodity based upon the ranking of said saleable commodity by said user. 2/32 START 202 _ _ Receiving one or more descriptors to allow for 200 identification of vendor' s property 204 Retrieving valuation date corresponding to one or more comparable real estate properties 206 Presenting to the vendor valuation data corresponding to each of the comparable properties 208 Enabling the vendor to rank their property relative to each of the comparable properties 210 Assigning an agreed listing value to the property based on the vendor' s ranking of the property STOP FIGURE 2